Gitea's collaborative-owner authorization path for reading cross-repository reusable workflows did not exclude fork pull request runs; as a result, an approved fork workflow that targets a private repository can read workflow files from another private repository that trusts the base repository's owner through collaborative-owner configuration, revealing private reusable workflow contents at caller-selected Git refs. This vulnerability does not grant write access or code execution in the target repository, but it does expose potentially sensitive workflow definitions, thereby affecting confidentiality of private workflow content and related settings. The weakness is an improper authorization flaw (CWE-280).

The vulnerability affects Gitea installations that enable collaborative-owner authorization for cross-repository reusable workflows, regardless of operating system or deployment environment. The fix has been introduced in releases after 1.27.3.

The CVSS score is 5.3, indicating moderate severity. EPSS score of <1% indicates a very low probability of exploitation, and the vulnerability is not listed in the CISA KEV catalog. The likely attack vector requires a collaborator or an authorized user on a base repository to approve a fork workflow; the attacker then triggers the fork pull request run to read the private workflow files. The exploit does not allow lateral movement or execution within the target repository, but it can leak workflow definitions that may contain internal references or other sensitive information.